This is just much more practical than a single method to lookup a single
collection by either the identifier or the name, then a `nil` check can
be used to check for its presence.

Conflicts in things like the ID should be automatically ignored, other
possible collisions like a collection's name is left to the dispatcher
to figure out.

For example, in the case of a duplicate collection (name), we can just
add a number, but if the event specifies a specific ID that already
exists, we don't care what the name is, we need to ignore it.

`WherePK` only works when you have set the ID on the target struct.

We already have it there anyway and it already does it by default.